This Discovery Shows Life Might Have Come From Space

Chiral molecules are “handy” molecules. Here’s how they’re helping us discover where else life might exist and how it originated on Earth.

A recent discovery in deep space could have profound implications regarding both the origins of life on Earth and the possible existence of extraterrestrial organisms. Why don’t these things make the headlines anymore? Oh, right.

We soldier on: As Trace Dominguez reports in today’s DNews dispatch, scientists recently discovered a complex molecule in deep space that bears significant resemblance to molecular structures here on Earth — structures that many believe are the key to organic life.

Using powerful radio telescopes, researchers were able to determine the chemical properties of a single molecule of propylene oxide floating around in a star-forming region near the center of the Milky Way. That’s kind of amazing in itself — spotting a single molecule 8,000 parsecs away — but the significant bit is that propylene oxide is asymmetrical in a very specific way. It’s what’s known as an “handed” molecule.

This particular kind of asymmetry is an actual chemical/geometric property called chirality. It involves mirror image compositions and is uncommonly hard to explain. Check out Trace’s video for some helpful visual aids.

Anyway, chirality is kind of akin to left-handedness or right-handedness, in that all living things favor and make use of only one type of any given chiral molecule. For example, DNA only twists in a right-handed screw, but it also uses only left-handed amino acids.

No one really knows why this is, but life on Earth has evolved so that only certain “handed” molecules fit with one another to assemble more complex organic structures. It’s safe to say that chiral molecules really are the secret to life as we know it.

Chirality has also been detected in molecules elsewhere in the solar system, but this is the first time we’ve spotted a chiral molecule in interstellar space. It suggests that chirality as a chemical property did not originate on Earth. If chiral molecules are present in the stellar dust out there in space, they could have reached Earth via meteorite or comet. That could explain how life came to exist on this planet.

It could also mean that life exists on other planets, or moons, or otherwise habitable bits of cosmic real estate. In terms of scientific discoveries, this is what we in the business refer to as a doozy.